As is known in the art, microwave assisted magnetic recording (MAMR) is a recording method to improve the areal density of a magnetic read/write head for use in a hard disk drive (HDD). MAMR enabled magnetic recording head utilizes a spin torque oscillator (STO) for generating a magnetic field having a microwave frequency. When the magnetic field from the write head is applied and current is conducted through the STO, the STO oscillates and the field is transferred to the medium. The AC magnetic field reduces the coercive force of the recording medium, thus high quality recording by MAMR may be achieved.
In hard disk drives, the read/write heads are flying closer and closer to the disk, and it is increasingly important to precisely detect the flying height and head disk impact. To do this, mechanical vibration of the read/write head is usually used to detect contact between the read/write head and the disk, because contact awareness is important to accurate flying height spacing. A dedicated contact sensor provides more accurate contact detection. The contact sensor is commonly referred to as a head-disk interference sensor (HDI). Some head-disk interference sensors are resistive temperature detectors that are configured into the head slider. The temperature change of the HDI sensor is used to indicate contact or the relative flying height of the slider. The HDI sensor has a current flowing through it for putting the sensor at a higher temperature than the local environment and providing a mean for monitoring its resistance change.
Both the STO and the HDI sensor require an additional electrical trace connection from the preamplifier to the head slider. Additionally, electrical connection pads are needed on the slider to accommodate both the STO and the HDI sensor.